Removal of Chlorinated Organic Compounds from Porous Materials by Using Ultrasound

Abstract

The removal performance of chlorinated organic compound from the porous material under ultrasonic irradiation was experimentally investigated. As the model PCB, o-dichlorobenzene was used. The solvent was hexane or dodecane. Wood chips impregnated with o-dichlorobenzene were used as the sample. The ultrasonic and solvent conditions were changed, and the removal ratio of o-dichlorobenzene from sample was measured. In order to examine the removal behavior of chlorinated organic compound from pore, the Stefan tube injected with o-dichlorobenzene was used as the sample. The pore and solvent conditions were changed, the interface position between o-dichlorobenzene and solvent in Stefan tube was measured and the penetration depth of solvent in Stefan tube was determined.By the ultrasonic irradiation, the removal ratio rapidly increased and became almost unity after 120 minutes for the sample with 10 mm in length. The removal rate for the ultrasonic irradiation was much higher than that for the shaking. The difference in removal ratio between the ultrasonic irradiation and the shaking became larger as the sample was bigger. The removal ratio increased with increasing sound pressure amplitude and became constant beyond a certain sound pressure amplitude. At the fixed sound pressure amplitude, the removal ratio at 28 kHz was nearly equal to that at 45 kHz. The removal ratio hardly depended on the solvent temperature. The removal ratio for degassed solvent was larger than that for non-degassed solvent.The penetration depth in Stefan tube had a maximum value against location of Stefan tube in solvent, but had no significant influence on size and depth of pore in Stefan tube. When the saturation degree of dissolved oxygen in solvent was 0.65, the penetration depth in Stefan tube was largest.